gfe-relnote: Add a quic::test::ServerThread::WaitUntil method and use it in quic end_to_end_test. Test only.
This is another attempt to deflake BadPacketHeaderFlags.
PiperOrigin-RevId: 293642314
Change-Id: I1809b8b56c50df7ef2de60d73ac30e9a4e8b35df
QUICHE (QUIC, Http/2, Etc) is Google‘s implementation of QUIC and related protocols. It powers Chromium as well as Google’s QUIC servers and some other projects.